O:o&#39;-dihydroxy azo dyestuffs and a process of making same



Patented Aug. 17, 1948 UNITED STATES PATENT OFFICE :O'-DIHYDROXY AZO DYESTUFFS AND A PROCESS OF MAKING SAME Achille Conzetti, Basel, Switzerland, assignor to the firm .l. R. Geigy A. G., Basel, Switzerland No Drawing.

Applicati No. 581,716. In Switze on March 8, 1945, Serial rland February 21, 1944 Section 1, Public Law 690, August 8, 1946 February 21, 1964 8 Claims. (Cl. 260-199) Patent expires Example 44.? kg. of 4-chloro-2-aminophenol-6-sulfonic acid are diazotised in the usual manner and the diazo compound is caused to run into a solution of 46.6 kg. of 1-carbo-methoxyamino-7- naphthol in 500 litres of water, of 22 kg. of 40% caustic soda lye and of 50 kg. of calcined sodium carbonate.

The finished dyestuff having been filtered dyes wool, when dyed according to the one-bath chroming process or according to the afterchroming process, in extremely light-fast, bluish grey shades of a very beautiful even color.

When, instead of the l-carbo-methoxyamino- 'l-naphthol, a compound having a higher carboalkoxy radical, such as l-carbo-ethoxy, l-carbopropoxyetc. -amino-'1-naphthol, is used, metallisable dyestuffs of similar properties are obtained.

What I claim is: V

1. Process for the manufacture of an o:o'-dihydroxy azo dyestuff which comprises coupling diazotised 4-ch1oro -2- aminophenol-fi-sulfonic acid in an alkaline medium with a l-carboalkoxyamino-l-naphthol.

2. Process for the manufacture of an 0:0- dihydroxy azo dyestufi which comprises coupling diazotised 4-chloro -2- aminophenol-G-sulfonic acid in an alkaline medium with l-carbomethoxyamino-7-naphthol.

3. Process for the manufacture of an 020'- dihydroxy azo dyestufi which comprises coupling diazotised 4-chloro -2- aminophenol-G-sulfonic acid in an alkaline medium with l-carboethoxyamino-'l-naphthol.

4. Process for the manufacture of an 0:0- dihydroxy azo dyestufi which comprises coupling diazotised 4-chloro -2- aminophenol-G-sulfonic acid in an alkaline medium with l-carbopropoxyamino-'l-naphthol.

5. An o:o'-dihydroxy azo dyestufi of the formula on OH HOaS N=N Anal 6. The o:o'-dihydroxy azo dyestuff of the formula $0113 being a dark blue powder and dyeing wool; when chromed, in bluish grey shades of excellent fastness to light.

'7. The o:o-dihydroxy azo dyestufi of the formula OH ()H HO S N=N EN (5 to 1 l O CzHs HOsS N=N HN to O1 4,

being a dark blue powder and dyeing wool, when chromed, in bluish grey shades of excellent fastness to light. 1

ACHILLE CONZETTI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain Aug. 15, 1938 

